Glutathione (Reduced) | CAS 70-18-8 | Tripeptide Antioxidant (Research Use Only) | Knowlux

Product Summary

Knowlux supplies reduced glutathione (GSH) as a purified tripeptide reference material for bench work, assay development and formulation pre-studies. The substance is a gamma-glutamyl-cysteinyl-glycine tripeptide carrying a free thiol group, isolated from microbial fermentation or produced synthetically to the same specification. Every consignment ships with a batch-tied analytical file (COA, SDS, chromatograms and origin documentation) so the material can be traced from drum to bench.

Specification Sheet

Parameter	Detail
Product	Glutathione, reduced form (GSH)
Synonyms	L-Glutathione reduced; gamma-L-Glutamyl-L-cysteinylglycine; Tathion
CAS	70-18-8
EC No.	200-725-4
Formula	C10H17N3O6S
Molecular weight	307.32 g/mol (307.321 by alternative atomic-weight set)
Appearance	White to off-white crystalline powder
Melting range	~182-192 C (with decomposition; some sources report 195-197 C)
Solubility	Freely soluble in water (>=50 mg/mL, clear and colourless); insoluble in ethanol, ether, acetone
Lipophilicity	logP ~ -5.41 (highly hydrophilic)
Assay	>=98.0% by HPLC (GSH); >=99.0% available on request
Identity	HPLC retention time plus LC-MS molecular ion ([M+H]+ 308.1)
Grade	Research grade
Water content	<=1.0% (Karl Fischer)
Storage	-20 C preferred, 2-8 C acceptable for short periods; amber vial, inert gas headspace
Hazard classification	No harmonised CLP/GHS classification; fine powder - dust irritation possible, use eye and respiratory protection
HS code	2930.90.00 (organo-sulphur compounds)
Pack sizes	5 g / 10 g / 25 g / 50 g / 100 g / 500 g / 1 kg
MOQ	10 g
Capacity	Gram to multi-kilogram scale
Origin	China

Structural and Physicochemical Notes

Glutathione is a tripeptide linking glutamate, cysteine and glycine through an unusual gamma-glutamyl bond, which protects the molecule from ordinary peptidase cleavage. The defining structural feature is the free thiol (-SH) on the cysteine residue, and essentially all of the molecule's redox behaviour flows from that group.

Three practical consequences follow from this structure:

Oxidative lability. In aqueous solution, GSH is readily oxidised to the disulfide dimer GSSG, especially under aerobic conditions, elevated temperature, or exposure to trace metal ions. A colour shift toward yellow or turbidity in solution is an early warning of oxidation. Amber glass and inert gas blanketing are not cosmetic choices.

pH sensitivity. The thiol is most stable at mildly acidic pH (around pH 3-5). Above pH 7, auto-oxidation accelerates markedly; alkaline buffers should be avoided in stock solutions. The isoelectric point is approximately 5.93.

Hydrophilicity. With a logP of approximately -5.41, GSH partitions overwhelmingly into water and shows essentially no membrane permeability. In vitro work normally uses aqueous stock solutions prepared fresh, without prolonged standing.

Grade Architecture - Read Before Ordering

Two redox forms circulate under the glutathione name, and they are not interchangeable:

Both forms share the same CAS number 70-18-8 only insofar as that CAS describes the parent glutathione molecule; the specification, not the CAS, tells you which redox state is in the drum. Buyers comparing quotations should confirm the oxidation state and the assay method - the two forms behave very differently in solution and in biological assays.

Analytical Control

Check	Technique
Assay (GSH)	HPLC-UV, external standard
Identity / mass confirmation	LC-MS, [M+H]+ 308.1
Moisture	Karl Fischer titration
Residual solvents	Headspace GC (on request)
Elemental impurities	ICP-MS (on request)
Appearance and mesh	Visual inspection, sieving

Each batch release is accompanied by the chromatogram set it was judged on, not a generic specification sheet.

Handling, Stability and Shelf Life

Keep the container closed, under inert gas where possible, and away from direct light. Working solutions in water are best prepared fresh and used within the same day; if storage is unavoidable, keep on ice and protect from air. Expect a visible shift toward yellow as oxidation to GSSG progresses - discolouration is a usable early warning sign. Sealed, light-protected storage at -20 C supports the retest period stated on the COA; repeated warming to room temperature accelerates oxidation.

Research Applications

• Certified reference material for glutathione quantification in biological matrices

• GSH/GSSG redox ratio determination and oxidative stress model calibration

• Protein purification via glutathione-agarose affinity chromatography (GST-tag elution)

• Thiol reactivity and enzyme cofactor studies (glutathione peroxidase, glutathione S-transferase)

• Antioxidant assay calibration (DPPH, ABTS, FRAP)

• Delivery-system and stability screening for thiol-containing formulations

Documentation and Traceability

Each lot is released against its own file: certificate of analysis with raw chromatograms, safety data sheet in the required language, certificate of origin, residual-solvent statement, elemental-impurity statement, and a stability/retest note. Method-transfer packages and supplier audit support can be arranged project by project.

Packing and Dispatch

Primary containment is an amber borosilicate vial or a high-barrier aluminium pouch with nitrogen headspace and a tamper-evident seal; secondary containment is a light-blocking carton with desiccant. Shipments leave Hubei within the lead time stated on the quotation, ambient by default, with cold packs and a temperature logger where the route or season requires it. Export paperwork (invoice, packing list, COA, SDS, origin certificate) is prepared before dispatch, not after.

About Knowlux

Knowlux Biotechnology operates from Hubei, China, as a GMP-oriented supplier of peptides, active substances and fine-chemical research compounds. Our customer base spans academic laboratories, CDMOs, formulation developers and distributors across more than 40 countries. Beyond catalogue supply we handle custom synthesis, bespoke pack sizes and documentation packages built to a client's audit template.

Compliance and Use Restriction

This material is released strictly for laboratory research use. It must not be administered to humans or animals, must not be used in diagnosis or therapy, and is not offered for retail, personal or household use.

Glutathione is authorised in many markets as a food additive (antioxidant), a cosmetic ingredient, and a pharmaceutical active substance in certain injectable and oral formulations. Those regulatory positions attach to compliant food-, cosmetic- and pharmaceutical-grade supply chains; they do not apply to, and are not represented by, this research-grade lot.

Statements describing published research are scientific background only. They are not medical advice, not a health claim, and not dosing or therapeutic guidance.